1. Field of the Invention
The present invention relates to an operation button used for portable apparatus of a camera and so forth. Particularly, the present invention relates to an operation button having a thin thickness.
2. Description of the Related Art
In recent years, portable apparatus of a camera and so forth have been contrived such that various functions can be operated in a limited space. As to one of such contraptions regarding a camera, it is known that an electric zooming operation and a mode setting operation can be performed by a single operation button. This is disclosed in Japanese Patent Laid-Open Publication No. 10-90768 (counterpart of U.S. Pat. No. 5,815,760).
An operation button described in the above publication is schematically shown in FIGS. 4A and 4B. A main part of the operation button 50 is constituted of a button body 51 having a disc shape. A central portion of the button body 51 is formed with a through hole 52 into which a boss 53a is inserted. The boss 53a projects from an inner frame 53 of a camera body. The button body 51 is fixed to the boss 53a by a screw-like retainer 55 so as not to trip. Moreover, the button body 51 is urged by a leaf spring 56 in a direction separating from the inner frame 53. Meanwhile, a button cover 57 for obscuring the retainer 55 is attached to a surface of the button body 51. The operation button 50 is provided with a plurality of depressed positions which are arranged in a circumferential direction of the operation button 50. Under the respective depressed positions, is disposed a switch 58 for detecting the depression of the operation button 50.
As shown in FIG. 4B, when one of the depressed positions of the operation button 50 is depressed by a finger, the button body 51 is swung around a position where an lower face of a flange 55a of the retainer 55 comes into contact with an upper face of the button body 51 which is opposite to the depressed position relative to the retainer 55. Owing to this, a protrusion 51a depresses the switch 58 to turn on it. When the finger depressing the operation button 50 is released, the switch 58 is turned off. At the same time, the button body 51 is pushed up by the leaf spring 56 and is returned to the original state.
The above operation button 50 has the depressed positions arranged in the circumferential direction thereof. Thus, the operation button 50 needs to have a space a secured along the round of the boss 53a in order to swing the button body 51. Hence, the operation button 50 is kept in a floating state that the whole of the operating button 50 is separated from the camera body by the leaf spring 56. Accordingly, there arises a problem in that the operation button 50 as a whole has a thick depth.
In view of the foregoing, it is a primary object of the present invention to provide an operation button of which thickness is adapted to be thin.
It is a second object of the present invention to provide an operation button in which it is possible to employ a thin urging member having urging force being relatively weak.
In order to achieve the above and other objects, the operation button according to the present invention comprises a button body and an urging member. The button body is swingably attached to an exterior wall of a portable apparatus, and has a plurality of depressed positions which are arranged in a circumferential direction of the operation button. The urging member urges the button body in a direction from the outside of the portable apparatus to the inside thereof. In virtue of this, return force for returning the button body to a neutral position is applied to the button body by the urging member. In the neutral position, the button body is kept so as not to incline.
Meanwhile, the button body is provided with a button cover for veiling the urging member so as to contain the urging member between the button body and the button cover. When one of the depressed positions of the button body is pressed, the button body is swung in a state that the bottom of the button body is a fulcrum. At this time, the urging member corresponding to the depressed position urges the button cover toward the outside of the portable apparatus. At the same time, a position of the button body opposite to the depressed position is urged toward the inside of the portable apparatus by the urging member. When the button body is stopped to be depressed, it is speedily returned to the neutral position due to synergism of two portions of the urging member.